Mobile communication device, PDAs, smartphones, or other mobile communication means may include additional functions which may be more frequently used as well as provide more diversified services. For example, mobile communication devices may include mobile camera modules with convergence devices capable of high-quality video capturing, auto focusing, and quick response (QR) code recognition and the like.
There has been increased attention related to camera technology such as Advanced Photo System type-C (APS-C) or higher interchangeable cameras and lenses.
In some cases, as the size of the camera sensor increases, the lens increases in size and weight, which may cause conditions to occur during image capturing such as AF velocity-related or noise issues upon video capturing, and image blurring or image shake due to the camera shake (or the movement of the camera) and the like.
For example, Japanese Patent Application Publication No. JP2013033178A, titled “OPTICAL SYSTEM, OPTICAL DEVICE, AND METHOD FOR MANUFACTURING OPTICAL SYSTEM,” discloses an image capturing optical system having a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power from an object. This image capturing optical system includes three focusing lenses in the second lens group and two optical image stabilizers (hereinafter, “OIS lens”) in the third group as a Fno 1.4-level, large-diameter optical system applies. In example, the term “Fno” may refer to Focal length/Entrance Pupil diameter characteristics of an optical system which represents f-number of an optical system that is the ratio of the lens's focal length to the diameter of the entrance pupil.
The image capturing optical system may have a plurality of focusing lenses and a plurality of OIS lenses and require an enlarged focusing actuator and OIS actuator for actuating focusing, which may result in an increase in the overall size of the lens barrel.
Further, Japanese Patent Application Publication No. JP2014081457A, titled “LARGE DIAMETER TELEPHOTO LENS SYSTEM,” discloses an image capturing optical system having a first lens group with a positive refractive power, a second lens group with negative refractive power, and a third lens group with positive refractive power from an object. The second lens group in the image capturing optical system includes a lens system, which is a focus lens group moving in a direction of an optical axis. The image capturing optical system uses two focusing lenses when a Fno 1.4-level large-diameter optical system applies.
The image capturing optical system includes a plurality of focusing lenses in the second lens group and has an enlarged focusing actuator, causing the overall optical system bulky. Further, the image capturing system may include an OIS-free optical system, which may cause image shake due to a camera shake when capturing video.
Further, Japanese Patent Application Publication No. JP2015041012A titled “INNER FOCUS LENS AND IMAGE CAPTURING DEVICE,” discloses a first lens group having positive refractive power, a second group having negative refractive power and a third group having positive refractive power from an object. The optical system disclosed therein has the second lens group configured of a sheet of element and the first lens group and the third lens group fastened on an optical axis, and the optical system has the second lens group move in an upper direction from the object along the optical axis to do focusing from a state of focusing an infinitely distant object up to a state of focusing for a closest distance object. The optical system overall includes seven lenses, and thus, it may be advantageous to implement a compact AF optical system. However, when applied to Fno 1.4 large-diameter optical systems, the configuration may make it difficult to correct chromatic aberration and astigmatism of large-diameter optical systems. Further, it may cause image blur due to camera shake when taking a video because it is an OIS-free optical system.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.